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Wyświetlanie 1-30 z 30
Tytuł:
Extraction Factor Of Pure Ammonium Paratungstate From Tungsten Scraps
Współczynnik ekstrakcji czystego parawolframianu amonu z odpadów wolframowych
Autorzy:
Pee, J-H.
Kim, G. H.
Lee, H. Y.
Kim, Y. J.
Powiązania:
https://bibliotekanauki.pl/articles/356567.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
raw material
recycling
ammonium paratungstate
tungsten scraps
extraction
surowce
recykling
parawolfrawian amonu
odpady wolframowe
ekstrakcja
Opis:
Typical oxidation process of tungsten scraps was modified by the rotary kiln with oxygen burner to increase the oxidation rate of tungsten scraps. Also to accelerate the solubility of solid oxidized products, the hydrothermal reflux method was adapted. By heating tungsten scraps in rotary kiln with oxygen burner at around 900° for 2hrs, the scraps was oxidized completely. Then oxidized products (WO3 and CoWO4) was fully dissolved in the solution of NaOH by hydrothermal reflux method at 150° for 2hrs. The dissolution rate of oxidized products was increased with increasing the reaction temperature and concentration of NaOH. And then CaWO4 and H2WO4 could be generated from the aqueous sodium tungstate solution. Ammonium paratungstate (APT) also could be produced from tungstic acid using by aqueous ammonium solution. The morphologies (cubic and plate types) of APT was controlled by the stirring process of purified solution of ammonium paratungstate.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1403-1405
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extraction Factor Of Tungsten Sources From Tungsten Scraps By Zinc Decomposition Process
Współczynnik ekstrakcji związków wolframu z odpadów wolframowych w procesie rozkładu cynku
Autorzy:
Pee, J-H.
Kim, G. H.
Lee, H. Y.
Kim, Y. J.
Powiązania:
https://bibliotekanauki.pl/articles/354774.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
raw material
recycling
zinc decomposition process
tungsten carbide
tungstic acid
surowce
recykling
proces rozkładu cynku
węglik wolframu
kwas wolframowy
Opis:
Decomposition promoting factors and extraction process of tungsten carbide and tungstic acid powders in the zinc decomposition process of tungsten scraps which are composed mostly of tungsten carbide and cobalt were evaluated. Zinc volatility was suppressed by the enclosed graphite crucible and zinc volatilization pressure was produced in the reaction graphite crucible inside an electric furnace for ZDP (Zinc Decomposition Process). Decomposition reaction was done for 2hours at 650°, which 100% decomposed the tungsten scraps that were over 30 mm thick. Decomposed scraps were pulverized under 75μm and were composed of tungsten carbide and cobalt identified by the XRD (X-ray Diffraction). To produce the WC(Tungsten Carbide) powder directly from decomposed scraps, pulverized powders were reacted with hydrochloric acid to remove the cobalt binder. Also to produce the tungstic acid, pulverized powders were reacted with aqua regia to remove the cobalt binder and oxidize the tungsten carbide. Tungsten carbide and tungstic acid powders were identified by XRD and chemical composition analysis.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1311-1314
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Understanding the Oxide Dispersion Behavior of Yttria in Metal Matrix of MA956 Alloy through High-Energy Milling and Hot Press Sintering
Autorzy:
Swain, B.
Han, D.
Kim, G.-H.
Kong, M.-S.
Ahn, B.
Powiązania:
https://bibliotekanauki.pl/articles/351770.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ODS
mechanical alloying
high-energy milling
oxide particle distribution
Opis:
MA956 (Fe-Cr-Al) alloy powder was high-energy ball milled with various amount of yttria contents (1,2,3, and 4 wt.%) to fabricate an oxide dispersion strengthened alloy. The milled powders were then consolidated using hot press sintering at 1150°C. The surface morphology and crystal structure of MA956 powder during the high-energy milling depending on the yttria contents was investigated using particle size analysis, X-ray diffraction, and scanning electron microscopy. The microstructural analysis of sintered alloy was performed using transmission electron microscopy and energy dispersive spectroscopy to evaluate the dispersion behavior of yttrium oxide. The results showed that, as yttria contents increased, the oxide particles became finer and are uniformly distributed during the high-energy milling. However, after the sintering, the oxide particles were coarsened with more than 3 wt.% of yttria addition.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1377-1381
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of Nickel Powders by Reduction of Nickel Hydroxide Using the Taylor Fluid Flow
Autorzy:
Park, I.-J.
Kim, D.-W.
Kim, G.-H.
Chae, H.-J.
Jung, H.-C.
Powiązania:
https://bibliotekanauki.pl/articles/355021.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ni(OH)2
nickel
Taylor fluid flow
fine powder
Opis:
In this study, Ni(OH)2 was synthesized by the continuous reaction by the Taylor fluid flow and compared with those prepared from the conventional batch type reaction. The nickel powders were synthesized by reduction of Ni(OH)2 in an aqueous solution with hydrazine hydrate acting as the reductant. And then the characteristics of the nickel powder according to the synthesis method were compared. The average particle size of the synthesized Ni(OH)2 using Taylor reactor was generally decreased about 1.5~2.5 times more than the batch reaction. The nickel powders prepared by the batch reaction highly agglomerated with non-uniform particles. In the Taylor reaction, the agglomeration of particles was broken and uniform nickel powder was produced.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1443-1447
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hardness and Microstructure of Mixed Al-CNF Powder Extrusion
Autorzy:
Kim, D.-H.
Kim, T.-J.
Lim, S.-G.
Powiązania:
https://bibliotekanauki.pl/articles/351170.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-CNF composite
cold isotatic
presses
powder extrusion
LED
microstructure
Opis:
In this study, mechanical properties and microstructures of extruded aluminum matrix composites were investigated. The composite materials were manufactured by two step methods: powder metallurgy (mixture of aluminum powder and carbon fiber using a turbular mixer, pressing of mixed aluminum powder and carbon fiber using a cold isostatic pressing) and hot extrusion of pressed aluminum powder and carbon fiber. For the mixing of Al powder and carbon fibers, aluminum powder was used as a powder with an average particle size of 30 micrometer and the addition of the carbon fibers was 50% of volume. In order to make mixing easier, it was mixed under an optimal condition of turbular mixer with a rotational speed of 60 rpm and time of 1800s. The process of the hot-extrusion was heated at 450°C for 1 hour. Then, it was hot-extruded with a condition of extrusion ratio of 19 and ram speed of 2 mm/s. The microstructural analysis of extruded aluminum matrix composites bars and semi-solid casted alloys were carried out with the optical microscope, scanning electron microscope and X-ray diffraction. Its mechanical properties were evaluated by Vickers hardness and tensile test.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1267-1270
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Characterization of GaN/Polymer Composite p-n Junction with PEDOT Nanoparticle Interface Layer
Autorzy:
Kim, M.
Jin, S.
Choi, H.
Kim, G.
Yim, K.
Kim, S.
Nam, G.
Yoon, H.
Kim, Y.
Lee, D.
Kim, Jin
Kim, Jong
Leem, J.
Powiązania:
https://bibliotekanauki.pl/articles/1505152.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.61.Ey
81.15.Gh
Opis:
A heavily Si-doped GaN/polymer hybrid structure with p-type poly(3,4-ethylene-dioxythiophene):beta-1,3-glucan (PEDOT nanoparticle) interface layer has been fabricated. The Si-doped GaN thin film with carrier concentration of 1 × $10^{19} cm^{-3}$ was grown by metal-organic chemical vapor deposition. The PEDOT nanoparticle with various sizes ranging from 60 to 120 nm was synthesized via a miniemulsion polymerization process. The electrical conductivity of the PEDOT nanoparticle is less than 1.2 S/cm. The current-voltage (I-V) characteristic of the hybrid structure shows diode-like behavior. The I-V characteristic was examined in the framework of the thermionic emission model. The ideality factor of the structure without PEDOT nanoparticle interface layer is 12.9. However, the ideality factor of the hybrid structure with PEDOT nanoparticle interface layer is obtained as 1.9. The value of ideality factor is dramatically decreased by inserting the PEDOT nanoparticle interface layer.
Źródło:
Acta Physica Polonica A; 2011, 119, 6; 875-879
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Properties of Multi-Stacked InAs Quantum Dots Embedded in GaAs/InGaAs Strained Layer and its Annealing Behaviors
Autorzy:
Kim, D.
Kim, G.
Jeon, S.
Cho, M.
Choi, H.
Kim, M.
Lee, D.
Kim, J.
Eom, G.
Leem, J.
Powiązania:
https://bibliotekanauki.pl/articles/1537752.pdf
Data publikacji:
2010-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
78.55.Cr
81.05.Ea
Opis:
Multi-stacked InAs QDs embedded in ten periods of GaAs/$In_{0.1}Ga_{0.9}As$ strained layers were grown by MBE and their optical properties were investigated by using PL spectroscopy. For the QDs embedded in ten periods of GaAs/$In_{0.1}Ga_{0.9}As$ strained layers, the PL intensity is enhanced about 4.7 times and a narrower FWHM of 26 meV is observed compared to those of the conventional multi-stacked QDs. The PL spectra of the InAs QDs show blue-shifts of about 50 meV with increasing annealing temperature up to 850°C. At annealing temperature of 600°C, the FWHM of the PL peak is reduced to 16 meV and PL intensity is enhanced compared to those of the as-grown sample, which indicates improvement of size uniformity and crystal quality of the QDs.
Źródło:
Acta Physica Polonica A; 2010, 117, 6; 941-944
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Similarity of chromosome structure among Populus tremula var. davidiana, Populus alba and their hybrids revealed by FISH karyotype analysis
Autorzy:
Kim, Y.G.
Kwon, S.H.
Kang, H.I.
Yoem, D.B.
Kim, K.W.
Kim, H.H.
Kang, K.S.
Powiązania:
https://bibliotekanauki.pl/articles/2077655.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Karyotype analysis
Fluorescence in situ hybridization
Ribosomal DNA site
Poplar
Cytogenetics
Opis:
The genus Populus is one of the important tree species in Korean peninsula and many other coun- tries in the world. It represents the model species of forest genomics because it grows fast and reproduces rapidly. In this reason, their genetic characteristics have been well studied and the whole genome has been sequenced completely in some species. However, cytogenetic study of the genus Populus has been limited. In the present study, karyotypes of Korean aspen (P. tremula var. davidiana), Silver poplar (P. alba) and their two hybrids, Suwon aspen (P. tremula var. glandulosa) and Hyun aspen (P. alba × P. tremula var. glandulsa) were analyzed by means of the fluorescence in situ hybridization (FISH). Root samples were collected from mature trees in the demonstration forest, located at Suwon, Kyonggi province in South Korea. The fresh root cells were examined by DAPI (4’,6-diamidino-2-phenylindole) staining and FISH using 45S rDNA and 5S rDNA probes. As the results, the chromosome compositions of all species were the same as 2n = 38. The karyotype formulas of Korean aspen, Silver poplar, Suwon aspen and Hyun aspen were 28m + 6sm + 4st (2sat), 26m + 10sm (2sat) + 2st, 26m + 12sm (2sat) and 28m + 10sm (2sat), respectively. The four species had one pair of 45S rDNA site and one pair of 5S rDNA site in common with FISH karyotypes. The similarity of FISH karyotypes among four species indicated close genetic relationship and coexistence of their interspecific hybrids. This research will provide genetic information on cytogenetic research of Populus and genetic mapping that can be applied to the breeding program of Populus in the near future.
Źródło:
Dendrobiology; 2020, 83; 68-74
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect Of Carbon Nanotubes On The Properties Of Spark Plasma Sintered ZrO2/CNT Composites
Wpływ nanorurek węglowych na właściwości spiekanych metodą sps kompozytów ZrO2/CNT
Autorzy:
Shim, D. H.
Jung, S. S.
Kim, H. S.
Cho, H.
Kim, J. K.
Kim, T. G.
Yoon, S. J.
Powiązania:
https://bibliotekanauki.pl/articles/351266.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CNT
ZrO2
composite
SPS
kompozyty
Opis:
Zirconia matrix ZrO2/CNT composite materials reinforced with multiwall carbon nanotubes were fabricated using a spark plasma sintering technique. The effects of the amount of CNTs addition, sintering temperature and sintering pressure on the properties of the resulting ZrO2/CNT composites were examined. 0 to 9 vol. % CNTs were dispersed in zirconia powder, and the resulting mixture was sintered. The electrical conductivity, hardness, flexural strength, and density were measured to characterize the composites. The friction and wear properties of the composites were also tested. The flexural strength and friction coefficient of the composites were improved with up to 6 vol.% of CNT addition and the flexural strength showed a close relationship with the relative density of the composite. The electrical conductivity increased with increasing proportion of the CNTs, but the efficiency was reduced at more than 6 vol.% CNTs.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1315-1318
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of an Incentive-Based Obesity Management Program in a Workplace
Autorzy:
Hwang, G.
Yoon, C.
Jung, H.
Kim, Y.
Powiązania:
https://bibliotekanauki.pl/articles/90493.pdf
Data publikacji:
2011
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
obesity
workplace
incentive
BMI
Opis:
This study is to analyze the effectiveness of an incentive-based obesity management program (the Midas Project aimed to improve good health habits) at an electronics company in 2005. A total of 95 company participants with a high body mass index (BMI) were recruited for a health promotion program for 3 months that awarded gold medals as an incentive for body fat loss. BMI decreased from 28.8 to 27.8 kg/m² (p = .000), body weight decreased from 87.2 to 83.5 kg (p = .000), and body fat weight decreased from 25.4 to 23.3 kg (p = .000). Systolic and diastolic blood pressure decreased from 130.5 to 125.1 mmHg (p = .002), from 86.4 to 81.7 mmHg (p = .009). The percentage of participants exercising more than 3 times per week increased from 27.3 to 52.3% (p = .000). The percentage who avoided overeating at parties and midnight eating increased from 65.9 to 72.7% (p = .767) and 70.5 to 84.1% (p = .172), respectively. This incentive-based obesity management program was effective in improving not only BMI but also health status.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2011, 17, 2; 147-154
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Error reduction of the Doppler lidar signal using a re-normalization method
Autorzy:
Park, N G
Baik, S H
Park, S K
Kim, D L
Kim, D. H.
Powiązania:
https://bibliotekanauki.pl/articles/173914.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
injection-seeded laser
Doppler lidar
frequency locking
wind lidar
Doppler velocity measurement
Opis:
In this paper, we present a re-normalization method for a Doppler signal of a Doppler lidar system. For the Doppler lidar system, we used an injection-seeded pulsed Nd:YAG laser as a transmitter and an iodine cell as a Doppler frequency discriminator. A frequency locking system that uses the absorption feature of iodine gas is too sensitive to the external or internal noises (iodine cell temperature instability, laser frequency fluctuation, environmental noises, etc.) to maintain its locking point ideally, and this frequency locking error makes the Doppler lidar system acquire the noises as the Doppler frequency shifts. To reduce the Doppler signal error induced by a frequency locking error, we used a re-normalization method by an addition of a laser beam path separated from a transmitter to the Doppler frequency discriminator for re-normalization. In this method, fluctuations of the Doppler signal were reduced using the reference signal. The reduced amount of standard deviation between the Doppler signal and the re-normalization signal was 4.838×10–3 and the Doppler signals showed a 53.3% fluctuation reduction of the averaged error value by this method.
Źródło:
Optica Applicata; 2014, 44, 1; 103-111
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of acute lipopolysaccharide-induced toxemia model on some neglected blood parameters
Autorzy:
Adam, G.O.
Lee, H.R.
Lee, S.J.
Kim, S.J.
Kim, G.B.
Kang, H.S.
Powiązania:
https://bibliotekanauki.pl/articles/2087627.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Toxemia
lipopolysaccharide
base excess
pH
animal model
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 4; 665-671
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of InAs Coverage on Transition of Size Distribution and Optical Properties of InAs Quantum Dots
Autorzy:
Kim, G.
Jeon, S.
Cho, M.
Choi, H.
Kim, D.
Kim, M.
Kwon, Y.
Choe, J.
Kim, J.
Leem, J.
Powiązania:
https://bibliotekanauki.pl/articles/1535820.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Hi
68.37.Ps
78.55.Cr
78.67.Hc
Opis:
The influence of InAs coverage on the formation of self-assembled quantum dots grown by molecular-beam epitaxy was investigated by atomic force microscopy and photoluminescence measurements. As the InAs coverage increased from 2.0 to 3.0 monolayers, the quantum dot density decreased from 1.1 × $10^{11}$ to 1.36 × $10^{10} cm^{-2}$. This result could be attributed to the coalescence of neighboring small InAs quantum dots resulting in the formation of much larger InAs quantum dots with lower quantum dot density. Atomic force microscopy results revealed that as the InAs quantum dot coverage increased, the transition of size distribution of InAs quantum dots from single-modal to multimodal occurred. The temperature-dependent photoluminescence spectra showed that the photoluminescence spectra red shifted and the photoluminescence peak intensity decreased as the InAs coverage increased. The thermal activation energy was strongly dependent on the InAs coverage, and for InAs quantum dots with 3.0 ML thick InAs coverage, this energy was estimated to be 147 meV.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 673-676
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photodynamic therapy of red and blue lights on Malassezia pachydermatis: an in vitro study
Autorzy:
Kim, W.R.
Bae, S.G.
Oh, T.H.
Powiązania:
https://bibliotekanauki.pl/articles/2087782.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dog
LEDs
PDT
Malassezia infection
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 1; 185-191
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxidation Behavior of Steel with Cr Content and Water Flow Rate
Autorzy:
Kim, D.-J.
Kim, K. M.
Shin, J. H.
Cheong, Y. M.
Lee, E. H.
Lee, G. G.
Kim, S. W.
Kim, H. P.
Choi, M. J.
Lim, Y. S.
Hwang, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/351548.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steel
flow accelerated corrosion
Cr content
flow rate
surface oxides
Opis:
Fast water flow facilitates ferrous ion transport leading to flow accelerated corrosion (FAC) of carbon steel and the possibility of a large accident through a failure of a secondary pipe in a nuclear power plant. Ion transport is directly linked to oxide properties such as the thickness, chemical composition and porosity. This work deals with a precise observation of the cross section of the corroded specimen focusing on an oxide passivity and its thickness using SEM (scanning electron microscope) and TEM (transmission electron microscope) as well as an apparent weight loss and a surface observation for the specimens corroded using a rotating cylindrical electrode autoclave system in pure water of pH 7 at 150°C having dissolved oxygen below 1 ppb within a flow rate range of 0 to 10 m/s. The Cr content in steel was changed from 0.02 to 2.4 wt%. Increasing the Cr content in the alloy, the FAC rate and oxide thickness decreased. The oxide porosity tends to decrease with the Cr content and immersion time owing to the development of Cr containing oxide. The oxidation behavior is not changed with the immersion time.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1383-1387
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Surface Characteristics and Physical Properties on Biodegradable Magnesium-Calcium Alloys by Anodic Oxidation
Autorzy:
Kim, J.
Lee, J.
Yang, H.
Park, S.
Lim, H.
Oh, G.
Yun, K.
Powiązania:
https://bibliotekanauki.pl/articles/1191716.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
87.85.jc
Opis:
The purpose of this study was to determine the effect of calcium (Ca) on the surface characteristics and physical properties of magnesium-calcium alloys after anodization. A novel binary alloy Mg-xCa (in which x=0.5, 1, or 5 wt.%) was cast by combining magnesium (99.9%) and calcium (99.9%) in an argon gas (99.99%) atmosphere. A magnesium alloy rod having a diameter of 15 mm was cut into discs, each 2 mm thick. The specimens were subjected to anodic oxidation at 120 V for 15 minutes at room temperature in an electrolyte solution consisting of calcium gluconate, sodium hexametaphosphate, and sodium hydroxide. Surface and cross-sectional morphological changes were observed using scanning electron microscopy, and the microstructures and phases were detected by means of X-ray diffraction. Hardness and surface roughness were assessed by means of a Vickers hardness tester and a surface roughness meter, respectively. The results show that the physical properties of these magnesium-calcium alloys have been improved, because it was possible to control the dissolution rate according to the amount of calcium added.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 736-741
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphology of strobili at different development positions and cone and seed characteristics of Pinus densiflora f. multicaulis
Autorzy:
Kwon, S.H.
Kim, Y.G.
Kang, H.I.
Shim, D.
Kang, K.S.
Powiązania:
https://bibliotekanauki.pl/articles/2078259.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
bisexual strobili
sex reversal
microsporangia
megasporangia
cone analysis
Opis:
Pinus densiflora f. multicaulis is a rare and unusual form of genus Pinus. It has excellent ornamen- tal values due to many trunks from its root collar, and produces female, male, and bisexual strobili on the same tree. However, there is limited study whether the bisexual strobili are functional, mature lateral cones produce filled seeds, and the seeds from the mature lateral cones germinate and grow as well as those from mature apical cones. The structure of apical female, and lateral male and bisexual strobili were analyzed in an open-pollination-progeny population. The strobili were photographed to obtain external, cross-section, and radial-section images using a 45× stereoscopic microscope. Radial sections of strobili were imaged using scanning electron microscopy. Characteristics of apical and lateral cones and seeds were surveyed by cone analysis and germination test. P. densiflora f. multicaulis developed typical female strobili apically, and ordinary male and bisexual strobili laterally. Additionally, female strobili developed laterally whereas the male strobili were normally located. The mature lateral female strobili had the same structure as the apical female. In the mature bisexual strobili, the proportion of male and female tissue was unequal. The cones developed from lateral female strobili showed highly significant differences in the length, width, and weight, being shorter (32.7%), narrower (26.9%), and lighter (59.8%) than those from apical female strobili. Both types produced filled seeds and seedlings, and well significant positive correlations were found among characteristics of seeds from apical and lateral female strobili. The initial seed germination rate of the seeds from apical female strobili was higher than that of seeds from lateral female strobili, but the difference decreased over time. The viability and spatial distribution of the female and male tissue of bisporangiate cones, and their frequent occurrence suggests a common mechanism for the production of bisporangiate structures in seed plants.
Źródło:
Dendrobiology; 2021, 85; 51-59
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on the effect of coal particle size on biodepyritization of high sulfur coal in batch bioreactor
Autorzy:
Singh, S.
Srichandan, H.
Pathak, A.
Gahan, Ch. S.
Lee, S.
Kim, D. J.
Kim, B. G.
Powiązania:
https://bibliotekanauki.pl/articles/778523.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
biodepyritization
coal
pyrite
stirred tank bioreactor
Opis:
The moderate thermophilic mix culture bacteria were used to depyritize the Illinois coal of varying particle sizes (-100 μm, 100-200 μm, +200 μm). Mineral libration analysis showed the presence of pyrite along with other minerals in coal. Microbial depyritization of coal was carried out in stirred tank batch reactors in presence of an iron-free 9K medium. The results indicate that microbial depyritization of coal using moderate thermophiles is an efficient process. Moreover, particle size of coal is an important parameter which affects the efficiency of microbial depyritization process. At the end of the experiment, a maximum of 75% pyrite and 66% of pyritic sulphur were removed from the median particle size. The XRD analysis showed the absence of pyrite mineral in the treated coal sample. A good mass balance was also obtained with net loss of mass ranging from 5-9% showing the feasibility of the process for large scale applications.
Źródło:
Polish Journal of Chemical Technology; 2015, 17, 1; 97-102
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Temperature Oxidation Property of SiC Coating Layer Fabricated by Aerosol Deposition Process
Autorzy:
Ham, G.-S.
Kim, S.-H.
Park, J.-Y.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/352142.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silicon carbide
aerosol deposition
coating
high temperature oxidation
Opis:
This study investigated the high temperature oxidation property of SiC coated layer fabricated by aerosol deposition process. SiC coated layer could be successfully manufactured by using pure SiC powders and aerosol deposition on the Zr based alloy in an optimal process condition. The thickness of manufactured SiC coated layer was measured about 5 μm, and coating layer represented high density structure. SiC coated layer consisted of α-SiC and β-SiC phases, the same as the initial powder. The initial powder was shown to have been crushed to the extent and was deposited in the form of extremely fine particles. To examine the high temperature oxidation properties, oxidized weight gain was obtained for one hour at 1000°C by using TGA. The SiC coated layer showed superior oxidation resistance property than that of Zr alloy (substrate). The high temperature oxidation mechanism of SiC coated layer on Zr alloy was suggested. And then, the application of aerosol deposited SiC coated layer was also discussed.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1347-1351
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manufacturing and Macroscopic Properties of Y2O3 Coating Layer on Ceramic (AlN) Substrate Fabricated by Aerosol Deposition
Autorzy:
Wi, D.-Y.
Ham, G.-S.
Kim, S.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/353052.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aerosol deposition
Y2O3 coating layer
AlN matrix
nano indentation
Opis:
This study attempted to manufacture an Y2O3 ceramic coating layer on a ceramic (AlN) substrate using aerosol deposition (AD) and investigated its macroscopic properties. Pure Y2O3 powder with a polygonal shape and average size of 5.0 μm was used as initial feedstock. Using aerosol deposition with suitable process conditions, an Y2O3 coating layer was successfully fabricated on aluminum nitride (AIN). The thickness of the manufactured coating layer was approximately 10 mm. The coating layer consisted of Y2O3 phase identical to that in the initial powder, and no additional oxides were identified. In regard to the roughness of the Y2O3 coating layer, the average roughness (Ra) measured 1.32 μm, indicating that the surface roughness was relatively even compared to the initial powder size (5 μm). Mechanical properties of the Y2O3 coating layer were measured using nano indentation equipment, and the indentation modulus of the Y2O3 coating layer fabricated by aerosol deposition measured 136.5 GPa. The interface of the coating layer was observed using TEM, and the deposition mechanism of the Y2O3 coating layer manufactured by aerosol deposition was also discussed.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1463-1466
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Conductivity and Microstructure of Copper Coated Graphite Composite by Spark Plasma Sintering Process
Autorzy:
Park, S. H.
Kim, D. B.
Lee, R. G.
Son, I. J.
Powiązania:
https://bibliotekanauki.pl/articles/355632.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metal matrix composites
thermal conductivity
thermal expansion
interfacial bonding
spark plasma sintering
Opis:
This study focuses on the fabrication of thermal management material for power electronics applications using graphite flake reinforced copper composites. The manufacturing route involved electroless plating of copper in the graphite flake and sintering process are optimized. The microstructures, interface, thermal properties, and relative density of graphite/Cu composites are investigated. The relative density of the composites shows 99.5% after sintering. Thermal conductivities and coefficients of thermal expansion of this composites were 400-480 Wm-1K-1 and 8 to 5 ppm k-1, respectively. Obtained graphite nanoplatelets-reinforced composites exhibit excellent thermo-physical properties to meet the heat dispersion and matching requirements of power electronic devices to the packaging materials.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1303-1306
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Characterization of CoCrFeNiMn High Entropy Alloy Powder Processed by Gas Atomization
Autorzy:
Park, T. G.
Lee, S. H.
Lee, B.
Cho, H. M.
Choi, W. J.
Kim, B. S.
Shin, K. S.
Kim, T.-S.
Powiązania:
https://bibliotekanauki.pl/articles/353649.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high entropy alloy
gas atomization
spark plasma sintering
CoCrFeNiMn
Opis:
In this study, precisely controlled large scale gas atomization process was applied to produce spherical and uniform shaped high entropy alloy powder. The gas atomization process was carried out to fabricate CoCrFeNiMn alloy, which was studied for high ductility and mechanical properties at low temperatures. It was confirmed that the mass scale, single phase, equiatomic, and high purity spherical high entropy alloy powder was produced by gas atomization process. The powder was sintered by spark plasma sintering process with various sintering conditions, and mechanical properties were characterized. Through this research, we have developed a mass production process of high quality and spherical high entropy alloy powder, and it is expected to expand applications of this high entropy alloy into fields such as powder injection molding and 3D printing for complex shaped components.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 1055-1059
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect Of SiC Particles On Sinterability Of Al-Zn-Mg-Cu P/M Alloy
Wpływ cząstek SiC na spiekalność proszku stopowego Al-Zn-Mg-Cu
Autorzy:
Rudianto, H.
Jang, G. J.
Yang, S. S.
Kim, Y. J.
Dlouhy, I.
Powiązania:
https://bibliotekanauki.pl/articles/351304.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metal matrix composites
powder metallurgy
sintering
heat treatment
kompozyty metalowe
metalurgia proszków
spiekanie
obróbka cieplna
Opis:
Premix Al-5.5Zn-2.5Mg-0.5Cu alloy powder was analyzed as matrix in this research. Gas atomized powder Al-9Si with 20% volume fraction of SiC particles was used as reinforcement and added into the alloy with varied concentration. Mix powders were compacted by dual action press with compaction pressure of 700 MPa. High volume fraction of SiC particles gave lower green density due to resistance of SiC particles to plastic deformation during compaction process and resulted voids between particles and this might reduce sinterability of this mix powder. Sintering was carried out under ultra high purity nitrogen gas from 565°-580°C for 1 hour. High content of premix Al-5.5Zn-2.5Mg-0.5Cu alloy powder gave better sintering density and reached up to 98% relative. Void between particles, oxide layer on aluminum powder and lower wettability between matrix and reinforcement particles lead to uncompleted liquid phase sintering, and resulted on lower sintering density and mechanical properties on powder with high content of SiC particles. Mix powder with wt90% of Alumix 431D and wt10% of Al-9Si-vf20SiC powder gave higher tensile strength compare to another mix powder for 270 MPa. From chemical compositions, sintering precipitates might form after sintering such as MgZn2, CuAl2 and Mg2Si. X-ray diffraction, DSC-TGA, and SEM were used to characterize these materials.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1383-1385
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Second Harmonic Generation, Beam Dynamics and Spatial Soliton Generation in Periodically Poled KTiOPO$\text{}_{4}$
Autorzy:
Kim, H.
Jankovic, L.
Stegeman, G.
Carrasco, S.
Torner, L.
Katz, M.
Eger, D.
Powiązania:
https://bibliotekanauki.pl/articles/2035660.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Jx
42.65.Ky
42.65.Tg
Opis:
Spatial solitons were investigated in periodically poled KTiOPO$\text{}_{4}$ under conditions of second harmonic generation and many new features associated with soliton generation in quasi-phase-matched samples were observed. The effects on the second harmonic generation tuning curves of the beam narrowing mechanisms responsible for soliton generation were found to be dramatic. It was demonstrated experimentally that the mutual collapse of the fundamental and harmonic beams is a complex phenomenon.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 107-119
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Investigations of Selected Materials by Low-Energy Ion Scattering Technique
Autorzy:
Goc-Jagło, D.
Sitko, D.
Jagło, G.
Kim-Ngan, N.-T. H.
Soszka, W.
Powiązania:
https://bibliotekanauki.pl/articles/2047339.pdf
Data publikacji:
2007-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.Rh
71.20.Be
71.20.Eh
77.80.Bh
Opis:
Surfaces of three selected materials were investigated by means of low-energy ion-scattering technique: (1) the magnetite (Fe$\text{}_{3}$O$\text{}_{4}$) exhibiting the so-called Verwey transition (T$\text{}_{V}$(bulk)=125 K) accompanied by a small cubic-monoclinic crystal distortion, (2) the intermetallic compound NdMn$\text{}_{2}$ undergoing an antiferromagnetic-paramagnetic phase transition (T$\text{}_{N}$=104 K) accompanied by a large crystal distortion with a volume change of 1%, and (3) the typical insulator BaTiO$\text{}_{3}$ with two structural transitions below 300 K. The primary energy of the (Ne$\text{}^{+}$, Ar$\text{}^{+}$) ion beam was in the range of 4-8 keV, and the low-energy ion-scattering spectra were collected in the temperature range of 85-300 K. A large influence from the Verwey transition on the neutralization and re-ionization of scattered ions from magnetite surface was observed, while no visible change at the magnetic phase transition in NdMn$\text{}_{2}$ was revealed in the low-energy ion-scattering spectra. A strong dependence of the characteristics of the low-energy ion-scattering spectra on the irradiated time was observed for BaTiO$\text{}_{3}$ indicating that this surface was heavily charged by ion bombardments.
Źródło:
Acta Physica Polonica A; 2007, 111, 5; 763-771
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery Of Electrodic Powder From Spent Nickel-Metal Hydride Batteries (NiMH)
Odzyskiwanie proszku elektrodowego ze zużytych akumulatorów niklowo-wodorkowych (NiMH)
Autorzy:
Shin, S. M.
Shin, D. J.
Jung, G. J.
Kim, Y. H.
Wang, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/356110.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nickel-metal hybride (NiMH)
electrodic powder
nickel
rare earth elements (REE)
thermal treatment
akumulator niklowo-wodorkowy
proszek elektrodowy
nikiel
pierwiastki ziem rzadkich
obróbka termiczna
Opis:
This study was focused on recycling process newly proposed to recover electrodic powder enriched in nickel (Ni) and rare earth elements (La and Ce) from spent nickel-metal hydride batteries (NiMH). In addition, this new process was designed to prevent explosion of batteries during thermal treatment under inert atmosphere. Spent nickel metal hydride batteries were heated over range of 300°C to 600°C for 2 hours and each component was completely separated inside reactor after experiment. Electrodic powder was successfully recovered from bulk components containing several pieces of metals through sieving operation. The electrodic powder obtained was examined by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) and image of the powder was taken by scanning electron microscopy (SEM). It was finally found that nickel and rare earth elements were mainly recovered to about 45 wt.% and 12 wt.% in electrodic powder, respectively.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1139-1143
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Consolidation Mechanism Of Porous Ti-6Al-4V Implant Prototypes Produced By Electro-Discharge-Sintering Of Spherical Ti-6Al-4V Powders
Mechanizm autokonsolidacji prototypów porowatych implantów wytworzonych przez spiekanie sferycznych proszków Ti-6Al-4V
Autorzy:
Lee, W. H.
Jo, Y. J.
Kim, Y. H.
Jo, Y. H.
Seong, J. G.
Van Tyne, C. J.
Chang, S. Y.
Powiązania:
https://bibliotekanauki.pl/articles/356277.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ti-6Al-4V
implant
porous
sintering
electrodischarge
porowatość
spiekanie
proszki spiekane
Opis:
Electro-Discharge-Sintering (EDS) was employed to fabricate Ti-6Al-4V porous implant prototypes from atomized powders (100 – 150 μm), that were subjected to discharges of 0.75 to 2.0 kJ/0.7g-powder from 150, 300, and 450 μF capacitors. Both fully porous and porous-surfaced Ti-6Al-4V compacts with various solid core sizes were self-consolidated in less than 86 – 155 μsec. It is known that EDS can simultaneously produce the pinch pressure to squeeze and deform powder particles and the heat to weld them together. The formation of a solid core in these prototypes depends on the amounts of both the pinch pressure and heat generated during a discharge. The size of the solid core and the thickness of the porous layer can be successfully controlled by manipulating the discharge conditions such as input energy and capacitance.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1185-1189
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compositional Dependence of Hardness of Ge-Sb-Se Glass for Molded Lens Applications
Zależność stężeniowa twardości szkła Ge-Sb-Se do zastosowań na formowane soczewki
Autorzy:
Park, J. K.
Lee, J. H.
Shin, S. Y.
Yi, J. H.
Lee, W. H.
Park, B. J.
Choi, J. H.
Kim, N. Y.
Choi, Y. G.
Powiązania:
https://bibliotekanauki.pl/articles/352228.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chalcogenide glasses
Ge-Sb-Se glass
infrared lens
molded lens
infrared camera
szkło
Ge-Sb-Se
soczewki formowane
twardość szkła
kamera termowizyjna
Opis:
Chalcogenide glass in the ternary Ge-Sb-Se system is inherently moldable, thus being considered as a strong candidate material for use in infrared-transmitting lens applications from the viewpoint of thermal and mechanical stability. In an effort to experimentally determine compositional region suitable for the molded lens applications, we evaluate its compositional dependence of hardness. Among the constituent atoms, Ge content turns out to exert a most conspicuous correlation with hardness. This phenomenological behavior is then explained in connection with the structural evolution that Ge brings about.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1205-1208
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carbon Co-Deposition During Gas Reduction of Water-Atomized Fe-Cr-Mo Powder
Autorzy:
Ali, B.
Choi, S. H.
Seo, S. J.
Maeng, D. Y.
Lee, C. G.
Kim, T. S.
Park, K. T.
Powiązania:
https://bibliotekanauki.pl/articles/352709.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
water atomization
Fe-based powder
oxide reduction
powder metallurgy
sinter-hardening alloys
Opis:
The water atomization of iron powder with a composition of Fe-3Cr-0.5Mo (wt.%) at 1600°C and 150 bar creates an oxide layer, which in this study was reduced using a mixture of methane (CH4) and argon (Ar) gas. The lowest oxygen content was achieved with a 100 cc/min flow rate of CH4, but this also resulted in a co-deposition of carbon due to the cracking of CH4. This carbon can be used directly to create high-quality, sinter hardenable steel, thereby eliminating the need for an additional mixing step prior to sintering. An exponential relationship was found to exist between the CH4 gas flow rate and carbon content of the powder, meaning that its composition can be easily controlled to suit a variety of different applications.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1119-1124
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of climate change impacts on grain sorghum production grown under free air CO2 enrichment
Autorzy:
Fu, T.
Ko, J.
Wall, G.W.
Pinter,Jr., P.J.
Kimball, B.A.
Ottman, M.J.
Kim, H.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/26201.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
crop simulation
climate change
grain yield
sorghum
Sorghum bicolor
productivity
plant production
carbon dioxide
Źródło:
International Agrophysics; 2016, 30, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-30 z 30

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